How severe is CVE-2015-0820?

CVE-2015-0820 has a CVSS 2.0 base score of 2.6, rated low severity.

Is CVE-2015-0820 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-0820?

CVE-2015-0820 primarily affects Mozilla Firefox. In total, 237 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-0820?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2015-0820 published?

CVE-2015-0820 was published on 2015-02-25 and last updated on 2026-06-17.

CVE-2015-0820

CVE-2015-0820 is a low-severity vulnerability in Mozilla Firefox with a CVSS 2.0 base score of 2.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Low (CVSS 2.0 base score 2.6)
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Mozilla Firefox
Published: 2015-02-25
Last modified: 2026-06-17

Description

Mozilla Firefox before 36.0 does not properly restrict transitions of JavaScript objects from a non-extensible state to an extensible state, which allows remote attackers to bypass a Caja Compiler sandbox protection mechanism or a Secure EcmaScript sandbox protection mechanism via a crafted web site.

Frequently asked questions

What is CVE-2015-0820?: Mozilla Firefox before 36.0 does not properly restrict transitions of JavaScript objects from a non-extensible state to an extensible state, which allows remote attackers to bypass a Caja Compiler sandbox protection mechanism or a Secure EcmaScript sandbox protection mechanism via a crafted web site.
How severe is CVE-2015-0820?: CVE-2015-0820 has a CVSS 2.0 base score of 2.6, rated low severity.
Is CVE-2015-0820 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-0820?: CVE-2015-0820 primarily affects Mozilla Firefox. In total, 237 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-0820?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2015-0820 published?: CVE-2015-0820 was published on 2015-02-25 and last updated on 2026-06-17.

References

Affected products (237)

cpe:2.3:o:opensuse:opensuse:13.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.3:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.4:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.5:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.6:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.6.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.7:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.7.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.8:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.9:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.9:rc:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.9.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.9.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.9.3:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.10:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:0.10.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0:preview_release:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.3:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.4:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.5:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.6:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.7:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.0.8:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.4.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5:beta1:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5:beta2:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5.0.1:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5.0.2:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5.0.3:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5.0.4:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5.0.5:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:1.5.0.6:*:*:*:*:*:*:*

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